[M2FanLCI]

What is a normal amount of turbo flutter for the N55 M2 with a manual transmission? Should there be none or is partial throttle flutter normal?

I noticed it flutter loudly a few times with the stock intake and thought, wow that's cool, sounds like a 90s turbo car. Being my first turbo car I didn't realize flutter is a problem. I recently put on a CTS intake and now that I can hear the turbo noises I notice that it generally flutters instead of the correct blow off woosh when I'm partial throttle to a quick full boost pull. When shifting in traffic driving slowly it will flutter. It only seems to blow off properly when I'm on the gas hard with boost built for more than a second or two.

Do yall think I have a problem with the blow off valve, vacuum lines, or is turbo flutter normal in partial boost situation with this motor? I could probably make a video if yall need, but I think my words got the point across.

[///MPhatic]

Flutter or rattle?

[M2lci_]

My car is DCT, but from what I've noticed it will only flutter in Traction mode and sometimes Comfort if I'm at a higher rpm (5k+ probably). Sport, Sport+, and DSC off never flutter, but are the 3 modes that produce the throttle liftoff 'brap' sound, along with the typical 'pshh' blowoff sound.

[shaneguags]

Originally Posted by M2lci_

My car is DCT, but from what I've noticed it will only flutter in Traction mode and sometimes Comfort if I'm at a higher rpm (5k+ probably). Sport, Sport+, and DSC off never flutter, but are the 3 modes that produce the throttle liftoff 'brap' sound, along with the typical 'pshh' blowoff sound.

why does it only wanna flutter in traction and comfort ? I do kinda notice it seems louder in comfort valves closed

[gsm2x3]

I have the same intake. Mine behaves the same. 🤷‍♂️

[Joebie]

I have a stock intake 6MT and i only notice flutter noises when going from full throttle to no throttle at low engine RPM, Like if you floor it in low 2nd gear and then let off shortly after.

I think that flutter noises under load are generally a bad thing but I'm not an expert, just perpetuating what I've read on the forums which is a dangerous thing to do :P

[M2lci_]

Originally Posted by shaneguags

why does it only wanna flutter in traction and comfort ? I do kinda notice it seems louder in comfort valves closed

I'm completely guessing here, but I think the car just routes all excess boost out through the exhaust in sport/sport+/DSC off so that there isn't anything slowing down the turbine. Flutter is caused by turbocharged air being forced back out the turbo and hitting compressor wheel, which will reduce its rpm, and in turn, less boost. So more than likely in comfort/traction off you aren't worried about throttle response and power so it sends everything through the turbo and hence the flutter. But again, just my guess. However I've never noticed this on any other EWG N55 car outside of the OG. All of those cars make the 'pshh' blowoff sound in every driving mode.

[shaneguags]

Originally Posted by M2lci_

I'm completely guessing here, but I think the car just routes all excess boost out through the exhaust in sport/sport+/DSC off so that there isn't anything slowing down the turbine. Flutter is caused by turbocharged air being forced back out the turbo and hitting compressor wheel, which will reduce its rpm, and in turn, less boost. So more than likely in comfort/traction off you aren't worried about throttle response and power so it sends everything through the turbo and hence the flutter. But again, just my guess. However I've never noticed this on any other EWG N55 car outside of the OG. All of those cars make the 'pshh' blowoff sound in every driving mode.

interesting ! thanks for your input

[Beenz]

You may need a video with the sound… to me, it sounds like you are describing anti-lag.
Unless you have a Fast and Furious style that 90s Japanese car, you probably shouldn’t be getting a ‘whoosh’ anyway…. So a flutter/ stutter is actually potentially just the sound of things working correctly. But like many of the other posts, I’m also just guessing at what you are referring to.

I’m also assuming you get the sound on minor and moderate lift off throttle.

[M2FanLCI]

Thanks for the replies. I did further testing and it seems that it just happens in MDM and comfort mode. Once I found this out I figured it just must be as designed. Its just further reason to drive in sport mode at a minimum.

You guys are right about when it happens and seems a few others have similar things happening. Must just be how the car is programmed in comfort and MDM modes.